The objective of this project is to determine and correlate the biomechanical properties of normal, normal aging and osteoarthritic articular cartilage with various histological grades. The experimental results will be utilized to develop biomechanical models of normal and pathological synovial joints. Solutions obtained from the models will be computerized to stimulate the normal and pathological lubrication and wear and tear processes of diarthroidal joints. Attempts will be made to hypothesize and verify various elements of the biomechanical theory of chondrodegeneration. Biomechanical testing of tissue will attempt to determine the layered variation of cartilage permeability, tensile and fatique strength. Viscoelastic indentation and creep studies will also be performed. All these biomechanical properties will be parametrically studied as functions of degrees of tissue hydration. Further, attempts will be made to ascertain the exact nature of the nonlinear pressure-permeability relationship as well as the nonlinear permeability-deformation relationship. These new nonlinear interactions are essential in the understanding of the overall mechanics of synovial joints. Finally, all tissue specimens will be comprehensively studied via the histological grading system as proposed by Mankin et al. Thus the proposed models of synovial joints will be able to predict the normal and pathological biomechanical processes during functions. BIBLIOGRAPHIC REFERENCES: "Mechanisms for Stress Relaxation in Articular Cartilage," V.C. Mow, H. Lipshitz and M.J. Glimcher, Extended Abstract, Trans. 1977 ORS, 1, 75, February 1977. "A Microstructural Model of the Stress-strain Behavior of Soft Connective Tissue," M.J. Askew and V.C. Mow, Extended Abstract, Trans. 1977 ORS, 1, 107, February 1977.